High rate ATM packet transmission over indoor radio channels

The design and performance of a high data rate modem which transmits ATM packets over indoor radio channels is discussed. A DFT-based multi carrier modulation technique with QPSK is used to mitigate ISI caused by a multipath spread of up to 250 ns. A rate one-half channel code is used to combat fading. Computer simulation is performed to investigate the system performance for five different multipath intensity profiles. The system performance is compared using a differentially coherent scheme and a coherent scheme based on channel estimation. The effects of carrier frequency offset and quantized soft decision decoding are discussed based on computer simulation results. Using various channel codes, an SNR of 14 to 21 dB is required at average BER of 10/sup -5/ to transmit a total of 155 Mb/s data over a bandwidth of 280 MHz.